1. Field of the Invention
The present invention relates generally to a Petri dish, and more particularly, to a Petri dish with predetermined sectors or grid pattern removably marked thereon, a marking sticker and a method of marking for obtaining the same.
2. Description of the Related Art
The study of microorganisms, such as yeast, bacteria, fungi, viruses, and the like, often require the growth of the same on a solid medium. One method for growing microorganisms on solid media is to use a Petri dish filled with a solidified agar. This is collectively referred to as a plate. Depending upon the experimental situation, the type of medium used in the agar plate may be considered rich, minimal, or an indicator.
The study of microorganisms also often require that cells placed on a plate be marked or labelled in some fashion in order to later distinguish one cell from an adjacent cell. This is particularly true when isolating single colonies of bacterial strains and when storing the same. Heretofore, the most cost efficient and simplest manner to accomplish this task was to draw the desired grids or sectors on the bottom of the Petri dish using a pen or permanent marker and ruler. This process, however, was quite time consuming for the scientist and often led to significant variation from one plate to another.
Another alternative, that was specifically designed to assist the scientist in replica plating, was a large opaque plate or holder having five wells that each hold one Petri dish. Typically, two wells were preprinted with a twenty-four square numbered grid and two wells were preprinted with a fifty square numbered grid. The center well was generally unnumbered and holds the main Petri dish containing the discrete colonies to be transferred. Thus, an unused Petri dish was placed in each well overtop of the preprinted grid and cells or microorganisms from the main dish were transferred to a prenumbered location within the Petri dish of each well.
Unfortunately, the Petri dishes within the wells had a tendency to shift during use, thereby causing misalignment with the preprinted wells therebelow and potential errors in the transfer procedure. Further, since the behavior of the microorganisms on the plate must be correlated with their particular sample location and number, the Petri dishes must be examined while they are positioned overtop of the preprinted wells. Not only was this inconvenient to the scientist, but misalignment of the Petri dish and the well may lead to inaccurate experiment results.
The use of the preprinted holder also required the individual Petri dishes as well as the holder to remain horizontal during the process. That is, the Petri dishes must be horizontal within the wells of the holder in order for the preprinted information to be visible to the user. This position, however, may become uncomfortable to the scientist during the transfer process. In addition, it is sometimes advantageous, particularly when relatively opaque growth media is used, to shine light through the Petri dish in order to better visualize the markings thereon as well as the microorganisms growing on the surface of the agar. Such preprinted holders of the prior art, however, were generally opaque, thereby preventing illumination of the markings and the growing microorganisms.
A further Petri dish available in the prior art to assist the scientist in identifying specific microorganisms was one having a grid or sector configuration molded into the bottom surface thereof. The molded dividing lines were generally difficult to see during the transfer process and while recording experiment results, however, and the scientist was still required to perform the time consuming chore of hand numbering or otherwise labelling each of the individual grid squares or sectors. The molded dishes also prevented the removal of the grid pattern when desired, such as, for instance to photographically record the results of an experiment. Most significantly though, since each configuration of grids or sectors required a different set of Petri dishes to be kept in inventory, the purchase and stocking costs associated with the molded Petri dishes was quite prohibitive.
Accordingly, there is a need for a simple and cost-efficient mechanism for marking Petri dishes in order to thereby obtain correlation of particular microorganisms on a plate with a predetermined sample location number or other label.